Risk factors for parvovirus B19 infection in pregnancy

CONTEXT

Parvovirus B19 infection during pregnancy has been associated with fetal death. However, the incidence of and risk factors for infection in pregnant women have not been well studied.

OBJECTIVES

To estimate a pregnant woman's risk of infection with parvovirus B19 in epidemic and endemic situations and to study risk factors for infection.

DESIGN

Population-based cohort study conducted between November 1992 and June 1994.

SETTING

Three regions in Denmark.

PARTICIPANTS

A total of 30946 pregnant women from a consecutive and population-based screening.

MAIN OUTCOME MEASURES

Specific IgG antibodies in serum samples obtained in the first trimester of pregnancy and from the newborn infant to assess past infection and seroconversion. Information on family structure, educational background, socioeconomic status, and pregnancy outcome was obtained from national registers.

RESULTS

Based on 30 946 serum samples, 65.0% of pregnant women had evidence of past infection. Annual seroconversion rates among susceptible women during endemic and epidemic periods were 1.5% (95% confidence interval [CI], 0.2%-1.9%) and 13.0% (95% CI, 8.7%-23.1 %), respectively. Baseline seropositivity was significantly correlated with increasing number of siblings, having a sibling of the same age, number of own children, and occupational exposure to children. Risk of acute infection increased with the number of children in the household as follows: 0 children odds ratio (OR), 1 (reference); 1 child OR, 3.17 (95% CI, 2.24-4.49); 2 children OR, 5.47 (95% CI, 3.55-8.45); 3 or more children OR, 7.54 (95% CI, 3.80-14.94). Having children aged 6 to 7 years resulted in the highest rate of seroconversion among mothers (6.8%; OR, 4.07; 95% CI, 1.89-8.73). Compared with other pregnant women, nursery school teachers had a 3-fold increased risk of acute infection (OR, 3.09; 95% CI, 1.62-5.89). Population-attributable risk of seroconversion was 55.4% for number of own children and 6.0% for occupational exposure.

CONCLUSIONS

The risk of infection is high for susceptible pregnant women during epidemics and associated with the level of contact with children. Nursery school teachers have the highest occupational risk, but most infections seem to be the result of exposure to the woman's own children.

Effects of family history and place and season of birth on the risk of schizophrenia

BACKGROUND

Although a family history of schizophrenia is the best-established risk factor for schizophrenia, environmental factors such as the place and season of birth may also be important.

METHODS

Using data from the Civil Registration System in Denmark, we established a population-based cohort of 1.75 million persons whose mothers were Danish women born between 1935 and 1978. We linked this cohort to the Danish Psychiatric Central Register and identified 2669 cases of schizophrenia among cohort members and additional cases among their parents.

RESULTS

The respective relative risks of schizophrenia for persons with a mother, father, or sibling who had schizophrenia were 9.31 (95 percent confidence interval, 7.24 to 11.96), 7.20 (95 percent confidence interval, 5.10 to 10.16), and 6.99 (95 percent confidence interval, 5.38 to 9.09), as compared with persons with no affected parents or siblings. The risk of schizophrenia was associated with the degree of urbanization of the place of birth (relative risk for the capital vs. rural areas, 2.40; 95 percent confidence interval, 2.13 to 2.70). The risk was also significantly associated with the season of birth; it was highest for births in February and March and lowest for births in August and September. The population attributable risk was 5.5 percent for a history of schizophrenia in a parent or sibling, 34.6 percent for urban place of birth, and 10.5 percent for the season of birth.

CONCLUSIONS

Although a history of schizophrenia in a parent or sibling is associated with the highest relative risk of having the disease, the place and season of birth account for many more cases on a population basis.

Investigations into the natural history of vestibular schwannomas

In the period from 1977 to 1996 143 vestibular schwannomas were diagnosed in 138 patients in the County of Aarhus, Denmark. The natural history of vestibular schwannomas was observed in 50 patients with 52 tumours who did not undergo immediate surgical removal of their tumour due to small tumour size, advanced age, poor general health and the patients' refusal of surgery. The management included serial CT- or MR-imaging and complete otoneurological evaluation. The imaging interval was between 6 months and 2 years and depended on the recorded growth rate. Thirty-three (64%) of the tumours showed continuous growth with a mean growth rate of 1.6 mm/year. In 11 (21%) of the tumours the size was unchanged and eight (15%) remitted. The last group consisted mainly of the largest tumours. Among the tumours with positive growth, 15 (45%) had a growth rate of 1 mm/year or less. Generally, our findings showed that approximately two-thirds of all the tumours did not grow, were getting smaller or had a growth rate sufficiently small to be simply watched. Additionally, our results suggest that some symptomatic tumours will grow to a certain point whereupon stagnation or remission occurs.

[Vestibular schwannoma. Incidence of the disease and the consequences]

During the period 1977-1996 142 vestibular schwannomas in 138 patients in a well-defined population in the County of Aarhus, Denmark were registered. The incidence of vestibular schwannomas changed from approximately six tumours pr. million inhabitants in the years 1977-1981 to 18 tumours pr. million in the period 1992-1996. Most tumours were operated, a smaller group of vestibular schwannomas were observed by repetitive tomographic imaging, due to small tumour size, advanced age, poor health conditions or the patient's refusal of operation. Whether the strategy for the treatment of vestibular schwannomas is an immediate operation or observation of selected patients, the future management of the increasing number of vestibular schwannomas will require an extension of the present surgical and MR-imaging capacity.

Acute mastoidectomy in a Danish county from 1977 to 1996 with focus on the bacteriology

To evaluate if the nature of acute mastoiditis (AM) treated surgically has changed during the last 20 years (1977-1996), the data from patients undergoing acute mastoidectomy were examined retrospectively. Cases with cholesteatomas and intracranial complications were excluded, while 79 patients (48% male) with a median age of 16 months were included. There was a history of infectious middle ear disease in 37% and the mean duration from onset of symptoms to admission was 9 days. The well-being was affected in 46 and 82% had fever. Purulent middle ear effusion was recognized in 92%. A subperiosteal abscess in 66% of the ears peroperatively. Specimens yielded growth of pathogens in 58%, predominantly gram positive bacteria, fully or partially sensitive to penicillin. Antimicrobial treatment before admittance masked or reduced more symptoms significantly. The patients from the last 10-year-period had less frequently acute otitis media in their history, shorter duration of hospitalization, and more frequently haemolytic Streptococcus group A. Conclusively, AM affects especially infants without previous middle ear disease. The clinical picture has become more subtle in time, probably due to antibiotics, and concomitantly the bacteriological pattern has changed.

The size of acoustic neuromas: CT and MRI

The growth rate of acoustic neuromas is very variable: some tumours grow rapidly, some do not grow and some even get smaller. When making treatment decisions, it may be important to have an idea of the growth rate of the individual tumour, and this is only possible when there are comparable examinations. We performed both CT and MRI on 15 patients. Two radiologists estimated the size of their acoustic neuromas. There was a significant difference between the two examiners' calculations of tumour volumes on CT and between the first examiner's CT and MRI volume calculations. No difference was found between the two MRI volume estimations or the second examiner's estimation of volumes on CT and MRI. Measurements of the maximal tumour diameter along the pyramid showed good concordance. We conclude that measurement the size of acoustic neuromas is reproducible with MRI and the measurement of the maximal tumour diameter is in practice a better parameter for comparison than calculation of real volume.

Prehospital treatment of patients with i.v. heroin overdose: what are we treating?

OBJECTIVE

To measure blood levels of morphine and additional drugs in patients suspected of intravenous (i.v.) heroin abuse and to evaluate the effects of antidote treatment.

DESIGN

Prehospital blood sampling in 52 patients.

RESULTS

Forty-five patients were blood-positive for heroin, eight of whom were hospitalized. Forty-one patients also had abused additional drugs: minor tranquilizers, ethanol, amphetamine, cocaine, and/or carbamazepine. Seven patients had taken either only methadone or ketobemidione: one was admitted. Treatment with increasing doses of naloxone indicated a necessity for hospitalization. Six of 14 patients treated with naloxone (1.8 mg were hospitalized. Seven patients had an extremely high blood level of morphine (0.2 mg/kg), that could be reverted with naloxone in moderate doses.

CONCLUSION

This study indicates that under prehospital conditions, it is difficult to identify a patient intoxicated only with intravenous heroin. Nearly all patients treated were cases of multiple drug/alcohol overdoses. Even the symptoms associated with extremely high blood levels of morphine could be reversed with naloxone in moderate doses.

Preconditioning the tympanic membrane: identification of cholesteatoma prone ears?

Preconditioning refers to changes in the mechanical properties of tissues due to repeated stress-strain experiments. Generally, after a number of cyclic deformation, a steady state is reached, where the experiment becomes repeatable, and the specimen is preconditioned. Tympanometric measurements of middle ear compliance also show increasing values for repeated trials until after 5 or 6 measurements, where steady state is reached. However, in some normal cases with high compliance it has previously been found that the tympanic membrane is not always able to reach a steady state, but displays larger and larger compliance over trials. This property may be characterized as a decreased resistance against pressure loads, which may lead to retractions, atelectasis, and cholesteatomas. Preconditioning was investigated in a group of 21 patients with cholesteatomas. Due to perforations and discharge the contralateral ear was measured. Nine tympanometries were recorded in one sequence. The increase in compliance between trials showed a complete overlap with a group of 25 normal subjects. For both groups good repeatability between trials with insignificant effect of preconditioning can be obtained after 4 trials.

Revision surgery in otosclerosis--an investigation of the factors which influence the hearing result

The hearing improvement obtained by revision surgery for otosclerosis has been assessed in 163 patients with a conductive hearing loss. Several different surgical techniques had been used at the primary operation. On average at revision a hearing improvement of 11 dB was obtained. The hearing improvement was related to the surgical technique of the primary operation, the middle ear abnormalities and the surgical technique used at revision. Patients in whom a small-fenestra-technique had been used for the primary as well as the revision procedure, had a better result than patients who had total removal of the footplate. Patients with adhesions and an eccentric prosthesis only showed a small hearing improvement. Patients with necrosis of the long process of the incus were also difficult to manage. Since the complication rate was low it does not seem to be more dangerous to perform a revision than to perform a primary operation. The results obtained by revision are poorer than can be obtained by the primary procedure. This indicates that in stapes surgery the greatest chance for hearing improvement is the first operation, therefore centralization of this type of operation should be considered.

Drugs in blood samples from unconscious drug addicts after the intake of an overdose

This investigation includes whole blood samples from 53 drug addicts found unconscious in the Copenhagen area with evidence of a heroin overdose. Heroin/morphine was detected in 85% of the patients and other opioids in 11%. One or more benzodiazepines, most often diazepam, were detected in 75% of the patients. A blood alcohol concentration higher than 1.00 mg/g was detected in 57% of the patients. Methadone was detected in seven patients, ketobemidone in four, amphetamine in five and cocaine in one. This investigation showed widespread multi-drug abuse and heroin/morphine alone was detected in only one patient. As indicators of heroin intake, 6-mono-acetylmorphine (MAM) and morphine were detected in this investigation.

[Size of acoustic neurinomas assessed by CT and magnetic resonance scanning]

Some acoustic neuromas do not grow or grow very slowly. It is therefore of value to compare the results of measuring the size of acoustic neuromas by either CT or Magnetic Resonance Imaging (MRI) scanning with a view to being able to observe the growth rate of these tumours. Fifteen patients with acoustic neuromas had both CT- and MRI-scans performed. Two trained radiologists evaluated the size of the tumours in a blinded fashion. There was a significant difference between one observer's calculations from the CT- and the MRI-scans, and also a significant difference between the two observers' calculations from the CT-scans. No difference in calculating tumour size was found between the two observers' calculations from the MRI-scans. It is concluded that the size of acoustic neuromas i evaluated more equally by two observers using MRI-scans than when using CT-scans. By the use of repeated MRI-scanning it is possible to keep patients with acoustic nouromas under observation and avoid operation in those patients where the tumour does not grow.

Common clonal chromosome aberrations in cytokine-dependent continuous human T-lymphocyte cell lines

Antigen-mediated T-cell proliferation is a transient phenomenon. Like other somatic cells, T lymphocytes generally show replicative senescence in vitro. However, we here show that cytokine-dependent continuous (immortal) T-cell lines can be established from skin biopsy specimens of inflammatory skin diseases. Continuous growth can be obtained by culturing T cells in medium supplemented with interleukin-2 and interleukin-4, but without antigen or antigen-presenting cells added. Loss of the T-cell antigen receptor complex is observed in some of the continuous T-cell lines. Most T-cell lines develop clonal chromosome aberrations during continuous growth. Aberrations for chromosomes 1, 2, 8, 16, and 18 are most commonly observed.

Appearance of isochromosome 18q can be associated with in vitro immortalization of human T lymphocytes

T lymphocytes cultured from a skin biopsy specimen of a patient with atopic dermatitis developed isochromosome 18q concomitant to escape from replicative senescence. Furthermore, two T-cell lines established from patients with cutaneous T-cell lymphoma also developed isochromosome 18q during continuous growth. The results indicate that a pathway leading to immortalization of human T lymphocytes could involve genes located at chromosome 18.

Regional cerebral activation during auditory stimulation in patients with cochlear implants

OBJECTIVE

To evaluate a possible change in the regional cerebral blood flow (rCBF) in the language-related cortical areas of the brain during stimulation of a cochlear implant.

METHODS

The rCBF was measured by single-photon emission tomography and inhalation of Xenon Xe 133, providing information on the regional functional level of the brain. A supplementary single-photon emission tomographic scan was also performed, using technetium Tc 99m hexamethylpropyleneamineoxime as a flow marker. The rCBF was measured during rest (baseline) and during auditory stimulation by presenting white noise and running speech to the ear with the implant.

PATIENTS

Five deaf patients who had undergone intracochlear or extracochlear implantation surgery.

RESULTS

As in subjects with normal hearing, notable activation was not found in the relevant primary auditory cortex on stimulation with white noise. Two of the patients with implants had an increase in the rCBF in the relevant contralateral hemisphere on stimulation with running speech, but in the other three patients, a notable increase was not detected. This lack of increase in the rCBF on speech stimulation was consistent with the lack of speech recognition experienced by the subjects when using the implant. In one subject, the implant had a beneficial effect on speech understanding that was associated with a significant increase in the cerebral blood flow in the Broca's speech area and Wernicke's second speech area.

CONCLUSIONS

Although the results are preliminary, the single-photon emission tomographic technique may be useful when evaluating the function of a cochlear implant. The method may also help select patients and/or ears for cochlear implantation. Four of five patients had functional defects of auditory relevant cortical areas, suggesting that their deafness might be associated with central impairment in addition to their cochlear defects.

In vitro genetically aberrant T-cell clones with continuous growth are associated with atopic dermatitis

Atopic dermatitis is a disease with a genetic predisposition affecting the immune system, with T lymphocytes participating in the immune dysregulation. Most in vitro T lymphocyte studies of atopic dermatitis have focused on antigen-specific T-cell clones. However, antigen-non-specific regulatory T lymphocytes may also take part in the pathway leading to antigen-specific clonal T-lymphocyte proliferation. T lymphocytes from skin biopsy specimens from three patients with severe atopic dermatitis were cultured in the presence of IL-2 and IL-4, but without antigen added. Initially, proliferation was oligo- or polyclonal, but in all cases overgrowth by T cells with clonal chromosomal aberrations was subsequently observed. These abnormal T-cell clones demonstrated continuous growth and complete or partial phenotypic loss of the T-cell antigen receptor complex. In summary, these findings suggest that a subset of aberrant skin-homing T lymphocytes is associated with atopic dermatitis.

Acoustic neuroma. Follow-up of 78 patients

This study assesses the outcome in 78 patients who had been diagnosed with acoustic neuroma over a period of 13 years. Forty-six patients were treated with translabyrinthine surgery, 13 with suboccipital surgery and/or ventricular drainage, and 19 patients (20 neuromas) were kept under observation. Of the 59 patients who had surgery, four died, 30 had problems with eating, drinking and balance, 17 had severe facial palsy, 21 discontinued their work after the operation and 30 had psychological problems. Twenty neuromas have not been operated upon and the patients have not deteriorated medically or socially. It is concluded that acoustic neuroma is a serious disease and that a conservative policy (wait and scan) is preferable in elderly patients.

Revision surgery in otosclerosis--operative findings in 186 patients

Over a 14-year-period 186 revision operations for otosclerosis were performed. In 90% of the patients the indication for revision was too large an air-bone-gap. A number of different surgical techniques had been used at the primary operation. The purpose of the investigation was to describe the middle ear abnormality at the revision operation. Most often adhesions, acentric prosthesis, reobliteration and necrosis of the long process of the incus were found. The middle ear abnormality found at revision operation was correlated to the primary surgical technique used and the information obtained can be of value, when a revision operation is considered. The surgical technique used at revision operation was determined by the operative findings. The best hearing improvement was obtained when a small-fenestration-technique was used primarily or as the method for revision. In revision stapes surgery, the experience of the surgeon is important and centralization of this type of operation is recommended.

[Exostosis of the external auditory meatus or ear canal nodes. A study of etiology and therapeutic results]

In this study we evaluated the relation between exposure of the ear canal to cold water and development of exostosis. Furthermore we wanted to evaluate the clinical outcome of surgical removal of the exostosis. The material consisted of a group of 15 winter bathers who had been exposed to cold water over a period varying from three to 45 years. All but one subject who had exposed the ear canal to cold water had developed exostoses of the ear canals. Follow-up examinations of nine patients after surgical removal of the exostosis revealed normal, well calibrated ear canals. Three winter bathers who continued the exposure to cold water developed a new exostosis.

[Severe respiratory depression after intake of a sustained-release morphine preparation]

A case of severe intoxication in a 33 year-old male who chewed a tablet of sustained-release morphine is presented. It is emphasized that patients are informed of the correct method of intake, especially of sustained-release agents since these are most likely to cause intoxication due to their high content of active substance.

[Acoustic neurinoma: observation prior to surgery]

During the period from 1977 to 1989 (both years included) 79 acoustic neurinomata were diagnosed in 76 patients in the County of Arhus. Twenty-four of these neurinomata were followed for varying periods clinically and radiographically. The symptoms of the patients and the results of successive computed-tomographic scans are mentioned. During the periods of observation, four patients were submitted to operation and operation was recommended in two cases. Seventeen patients are still under observation and are in good clinical condition with cessation or limited growth of the tumour in eight. These patients have been observed for between 1 and 13 years, on an average 4.5 years and are characterised by advanced age which averaged 61 years at the time of the diagnosis. The rate of growth of the tumour was calculated to be 1.1 mm per annum on an average with a variation from 0 mm to 4.8 mm per annum. As operative treatment of acouistic neurinoma exposes the patient to a not inconsiderable risk of deterioration the medical and/or socioeconomic status, the authors consider that an expectant and controlled attitude (wait and scan) is justified in elderly patients with acoustic neurinoma.